long context benchmark
ComplexFuncBench Leaderboard
ComplexFuncBench is a benchmark designed to evaluate large language models' capabilities in handling complex function calling scenarios. It encompasses multi-step and constrained function calling tasks that require long-parameter filling, parameter value reasoning, and managing contexts up to 128k tokens. The benchmark includes 1,000 samples across five real-world scenarios.
Updated Aug 17, 2026
Models7
Model coverage7
MetricScore
EvidenceB
ComplexFuncBench Ranking
Higher score ranks better on this benchmark.
Sort by
Rank | Model | Score | Percentile | Participants | Evidence | Evaluated |
|---|
| Rank01 | ModelOP | Score66.5% | Percentile100.0% | Participants7 | EvidenceC | Evaluated |
| Rank02 | ModelOP | Score65.5% | Percentile83.3% | Participants7 | EvidenceC | Evaluated |
| Rank03 | ModelAM Nova 2 SonicAmazon | Score65.2% | Percentile66.7% | Participants7 | EvidenceC | Evaluated |
| Rank04 | ModelOP | Score63.0% | Percentile50.0% | Participants7 | EvidenceC | Evaluated |
| Rank05 | ModelOP | Score49.3% | Percentile33.3% | Participants7 | EvidenceC | Evaluated |
| Rank06 | ModelOP | Score17.6% | Percentile16.7% | Participants7 | EvidenceC | Evaluated |
| Rank07 | ModelOP | Score5.7% | Percentile0.0% | Participants7 | EvidenceC | Evaluated |
ComplexFuncBench Highlights
The leading models and scores on this benchmark.
ComplexFuncBench Score Distribution
A closer view of the leading scores on this benchmark.
The Top AI Models for ComplexFuncBench
The first five results on this benchmark, with official price and output speed added where the model identity can be matched.
Ranking basisThis complexfuncbench AI model leaderboard uses descending score in the benchmark's original unit. The leaderboard ranking keeps matched price and speed data separate from benchmark evidence.
- 01OPGPT-4oOpenAI
- Score
- 66.5%
- Price
- $2.5 input / $10 output per 1M tokens
- Speed
- Up to 132 tok/s via OpenAI
Strengths
- Ranks #1 of 7 compared models
- 100th percentile on this benchmark
- C evidence result
Considerations
- This result measures ComplexFuncBench, not total model capability
- 02OPGPT-4.1OpenAI
- Score
- 65.5%
- Price
- $2.0 input / $8.0 output per 1M tokens
- Speed
- Up to 100 tok/s via OpenAI
Strengths
- Ranks #2 of 7 compared models
- 83th percentile on this benchmark
- C evidence result
Considerations
- This result measures ComplexFuncBench, not total model capability
- 03AMNova 2 SonicAmazon
- Score
- 65.2%
Strengths
- Ranks #3 of 7 compared models
- 67th percentile on this benchmark
- C evidence result
Considerations
- This result measures ComplexFuncBench, not total model capability
- 04OPGPT-4.5OpenAI
- Score
- 63.0%
- Speed
- Up to 50 tok/s via OpenAI
Strengths
- Ranks #4 of 7 compared models
- 50th percentile on this benchmark
- C evidence result
Considerations
- This result measures ComplexFuncBench, not total model capability
- 05OPGPT-4.1 miniOpenAI
- Score
- 49.3%
- Price
- $0.40 input / $1.6 output per 1M tokens
- Speed
- Up to 69 tok/s via OpenAI
Strengths
- Ranks #5 of 7 compared models
- 33th percentile on this benchmark
- C evidence result
Considerations
- This result measures ComplexFuncBench, not total model capability
Selection summary
Best AI Models for ComplexFuncBench
GPT-4o currently leads ComplexFuncBench with 66.5%. It is the top model on this specific benchmark, while the best LLM for the broader task should also be checked against other benchmarks, price and runtime.
Use this leaderboard with the supporting benchmark results and coverage details above. A leaderboard position summarizes the selected ranking signal; it does not replace workload-specific testing.
What is ComplexFuncBench?
What ComplexFuncBench measures and how its scores work.
ComplexFuncBench is a benchmark designed to evaluate large language models' capabilities in handling complex function calling scenarios. It encompasses multi-step and constrained function calling tasks that require long-parameter filling, parameter value reasoning, and managing contexts up to 128k tokens. The benchmark includes 1,000 samples across five real-world scenarios.
Scores are shown in ratio. This benchmark is not independently verified and has an evidence level of B.
- Family
- ComplexFuncBench
- Modality
- text
- Primary category
- long context
- Score direction
- higher
- LLMBoard eligible
- Yes
- Evaluation key
- complexfuncbench|llm-stats-current
Benchmark scores retain their original unit. Overall score eligibility is shown separately.
FAQ
Common questions about ComplexFuncBench.
Which model scores highest on ComplexFuncBench?
GPT-4o is currently ranked first with 66.5%.
What does ComplexFuncBench measure?
ComplexFuncBench is a benchmark designed to evaluate large language models' capabilities in handling complex function calling scenarios. It encompasses multi-step and constrained function calling tasks that require long-parameter filling, parameter value reasoning, and managing contexts up to 128k tokens. The benchmark includes 1,000 samples across five real-world scenarios.
Is a higher score better?
Yes. Higher values rank better for this benchmark.
How many models are compared?
7 model results are currently shown.
Does this benchmark affect the overall score?
Yes. This benchmark can contribute to the current LLMBoard capability score.